Extbase provides a Property Mapper to convert different values, like integers or arrays, to other
types, like strings or object.
In this example, we provide a string that will be converted to an integer:

It’s also possible to map to subtypes. In the above example, the FrontendUser has a sub-property
of type TYPO3\CMS\Extbase\Domain\Model\FrontendUserGroup. If you wanna map an incoming id,
you have to configure the mapper as per default he won’t map sub properties for security reasons: